Openstack Liberty Error: Unable to retrieve volume limit information.

After an Openstack Liberty deployment  you may encounter the following error: Error: Unable to retrieve volume limit information. OR Danger: There was an error submitting the form. Please try again.

unable to retreive size limit

These errors are a result of a miss-configuration within CINDER, to resolve this all you need to do is edit the ‘/etc/cinder/cinder.conf‘ file and make sure the following two lines exist

auth_uri = http://keystone_ip:5000
auth_url = http://keystone_ip:35357
auth_plugin = password
project_domain_id = default
user_domain_id = default
project_name = services
username = cinder
password = [ccinder password] <- find from answer file. password is stored in CONFIG_CINDER_KS_PW

After you had verified or added the lines you will need to restart the cinder services by running:

# service openstack-cinder-api restart
# service openstack-cinder-backup restart
# service openstack-cinder-scheduler restart
# service openstack-cinder-volume restart

Using multiple external networks in OpenStack Neutron

I haven’t found a lot of documentation about it, but basically, here’s how to do it. Lets assume the following:

  • you start from a single external network, which is connected to ‘br-ex’
  • you want to attach the new external network to ‘eth1’.

In the network node (were neutron-l3-agent, neutron-dhcp-agent, etc.. run):

  • Create a second OVS bridge, which will provide connectivity to the new external network:
ovs-vsctl add-br br-eth1

ovs-vsctl add-port br-eth1 eth1

ip link set eth1 up
  • (Optionally) If you want to plug a virtual interface into this bridge and add a local IP on the node to this network for testing:
ovs-vsctl add-port br-eth1 vi1 – set Interface vi1 type=internal

ip addr add dev vi1 # you may adjust your network CIDR, or set your system configuration to setup this at boot.
  • Edit your /etc/neutron/l3_agent.ini , and set/change:
gateway_external_network_id =

external_network_bridge =

This change tells the l3 agent that it must relay on the physnet<->bridge mappings at /etc/neutron/plugins/openvswitch/ovs_neutron_plugin.ini it will automatically patch those bridges and router interfaces around. For example, in tunneling mode, it will patch br-int to the external bridges, and set the external ‘q’router interfaces on br-int.

  • Edit your /etc/neutron/plugins/openvswitch/ovs_neutron_plugin.ini to map ‘logical physical nets’ to ‘external bridges’
bridge_mappings = physnet1:br-ex,physnet2:br-eth1
  • Restart your neutron-l3-agent and your neutron-openvswitch-agent
service neutron-l3-agent restart

service neutron-openvswitch-agent restart

At this point, you can create two external networks (please note, if you don’t make the l3_agent.ini changes, the l3 agent will start complaining and will refuse to work)

neutron net-create ext_net –provider:network_type flat –provider:physical_network physnet1 –router:external=True

neutron net-create ext_net2 –provider:network_type flat –provider:physical_network physnet2 –router:external=True

And for example create a couple of internal subnets and routers:

# for the first external net

neutron subnet-create ext_net –gateway – –enable_dhcp=False # here the allocation pool goes explicit…. all the IPs available..

neutron router-create router1

neutron router-gateway-set router1 ext_net

neutron net-create privnet

neutron subnet-create privnet –gateway –name privnet_subnet

neutron router-interface-add router1 privnet_subnet
# for the second external net

neutron subnet-create ext_net2 –allocation-pool start=,end= –gateway= –enable_dhcp=False

neutron router-create router2

neutron router-gateway-set router2 ext_net2

neutron net-create privnet2

neutron subnet-create privnet2 –gateway –name privnet2_subnet
 neutron router-interface-add router2 privnet2_subnet

Setting Up a Flat Network with Openstack Neutron

This setup will allow the VMs to use an existing network. In this example, eth2 is connected to this pre-existing network ( that we want to use for the OpenStack VMs.

All the configuration is done in the node dedicated to Nova Networking.

1. Set up the Open vSwitch bridge:

# ovs-vsctl add-br br-eth2
# ovs-vsctl add-port br-eth2 eth2

2. Set up /etc/network/interfaces (node’s IP is

auto eth2
iface eth2 inet manual
up ifconfig $IFACE up
up ip link set $IFACE promisc on
down ip link set $IFACE promisc off
down ifconfig $IFACE down

auto br-eth2
iface br-eth2 inet static

3. Tell Open vSwitch to use the bridge connected to eth2 (br-eth2) and map physnet1 to it /etc/neutron/plugins/openvswitch/ovs_neutron_plugin.ini:

network_vlan_ranges = physnet1
bridge_mappings = physnet1:br-eth2

4. Tell Neutron to not to use the metadata proxy in /etc/nova/nova.conf (otherwise you get a HTTP 400 when querying the metadata service):


Note that the metadata service is managed by Neutron as usual via the neutron-metadata-agent service anyway.

5. Create the network telling to use the physnet1 mapped above to br-eth2:

# neutron net-create flat-provider-network --shared  --provider:network_type flat --provider:physical_network physnet1

6. Create the subnet:

# neutron subnet-create --name flat-provider-subnet --gateway --dns-nameserver  --allocation-pool start=,end=  flat-provider-network

That’s it. Now VMs will get an IP of the specified range and will be directly connected to our network via Open vSwitch.